The present invention relates generally to processing of a binary image consisting of binary pixels as in the case of a character font image and, more particularly, to an image half-tone processor for expressing the binary image as a multi-gradated image containing half-tones and capable of providing a comparatively easy-to-see display or print, etc. for an output dot density.
In recent years, there has increasingly been a rapid enhancement in terms of MMI (Man-Machine Interface) owing to an advancement in GUI (Graphical User Interface) in computers. Corresponding to such a trend, there increases an occasion in which the image data containing the images and characters are displayed in a variety of sizes, or printed by a printer, etc. and outputted.
On the other hand, with a diversification of the display information, a prevailing type of display device is, though low of its resolution in a so-called monochrome display, capable of displaying with multi-gradations. For example, the great majority of liquid crystal display devices exhibiting a low resolution are capable of 8- or 16-gradation display containing half-tones in addition to two gradations in black and white.
By the way, a comparatively inexpensive output device, especially a small-sized display device is generally low of the resolution and tends to be hard to see enough to worsen a visual recognizability because of an image the outline of which becomes conspicuous of sharp ruggedness when displaying binary image data consisting of rather definite binary data. A more remarkable tendency of this sort can be seen in the liquid crystal display often used for particularly a carriable type appliance such as a so-called notebook type personal computer because of rectangular dots being uniform in terms of display dots.
When outputting letter, i.e., characters having the same logic size (e.g., 10.5 point) to a display device and a printer that are defined as outputting devices, a letter image, viz., a character image actually displayed on the display device and a character image printed by the printer are expressed with different numbers of dots on account of a difference in resolution between the outputting devices. Therefore, the display device generally exhibiting a lower resolution than the printer comes to display a conspicuously rugged rough image of the character.
It is an object of the present invention, which was contrived under such circumstances, to provide an image half-tone processor capable of giving an easy-to-see display with a high visual recognizability by converting a primary binary image (an original binary image) into a multi-gradated image and outputting the image based on the multi-gradation expression in a system for outputting the binary image by use of an outputting device possible of expressing it with the multi-gradations containing half-tones.
A first image half-tone processor according to the present invention comprises a pixel converting unit for weighting each of pixels of a primary binary image, and converting the primary binary image into a multivalued image consisting of weighted pixel values, a shift inversion processing unit for forming respectively a plurality of shift-inverted images into which the primary binary image is inverted and shifted in a plurality of peripheral directions corresponding to a pixel array of the primary binary image, a gradation processing unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the plurality of shift-inverted images obtained by the shift inversion processing unit, and an image outputting device for outputting the half-tone image formed by the gradation processing unit.
The shift inversion processing unit may be a unit for forming respectively four shift-inverted images into which the primary binary image is inverted and shifted in upper-, lower-, left- and right-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shift-inverted images obtained by the shift inversion processing unit.
The shift inversion processing unit may be a unit for forming respectively four shift-inverted images into which the primary binary image is inverted and shifted in left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shift-inverted images obtained by the shift inversion processing unit.
The shift inversion processing unit may be a unit for forming respectively eight shift-inverted images into which the primary binary image is inverted and shifted in upper-, lower-, left-, right-, left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the eight shift-inverted images obtained by the shift inversion processing unit.
The gradation processing unit may be a unit for additionally synthesizing the multivalued image obtained by the pixel converting unit and the plurality of shift-inverted images obtained by the shift inversion processing unit per pixel corresponding to the multivalued image.
A second image half-tone processor according to the present invention comprises a pixel converting unit for weighting eahc of pixels of a primary binary image, and converting the primary binary image into a multivalued image consisting of weighted pixel values, a shift processing unit for forming respectively a plurality of shifted images shifted in a plurality of peripheral directions corresponding to a pixel array thereof, a gradation processing unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the plurality of shifted images obtained by the shift processing unit, and an image outputting device for outputting the half-tone image formed by the gradation processing unit.
The shift inversion processing unit may be a unit for forming respectively four shift-inverted images into which the primary binary image is shifted in upper-, lower-, left- and right-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shift-inverted images obtained by the shift inversion processing unit.
The shift inversion processing unit may be a unit for forming respectively four shift-inverted images into which the primary binary image is shifted in left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shift-inverted images obtained by the shift inversion processing unit.
The shift inversion processing unit may be a unit for forming respectively eight shift-inverted images into which the primary binary image is shifted in upper-, lower-, left-, right-, left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the eight shift-inverted images obtained by the shift inversion processing unit.
The gradation processing unit may be a unit for additionally synthesizing the multivalued image obtained by the pixel converting unit and the plurality of shifted images obtained by the shift inversion processing unit per pixel corresponding to the multivalued image.
A third image half-tone processor according to then present invention comprises an enlarged image forming unit for forming a primary binary image having a size that is (xxc3x97y) times as large as a desired output size, a pixel converting unit for weighting each of pixels of the primary binary image, and converting the primary binary image into a multivalued image consisting of weighted pixel values, a shift inversion processing unit for forming respectively a plurality of shift-inverted images into which the primary binary image is inverted and shifted in a plurality of peripheral directions corresponding to a pixel array thereof, a gradation processing unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the plurality of shifted images obtained by the shift processing unit, a reduction processing unit for reducing the half-tone image formed by the gradation processing unit down to a size by a factor of (1/x)xc3x97(1/y), and an image outputting device for outputting the half-tone image formed by the reduction processing unit.
The shift inversion processing unit may be a unit for forming respectively four shift-inverted images into which the primary binary image is inverted and shifted in upper-, lower-, left- and right-directions, and the gradation processing unit ma be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shift-inverted images obtained by the shift inversion processing unit.
The shift inversion processing unit may be a unit for forming respectively four shift-inverted images into which the primary binary image is inverted and shifted in left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shift-inverted images obtained by the shift inversion processing unit.
The shift inversion processing unit may be a unit for forming respectively eight shift-inverted images into which the primary binary image is inverted and shifted in upper-, lower-, left-, right-, left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the eight shift-inverted images obtained by the shift inversion processing unit.
The gradation processing unit may be a unit for additionally synthesizing the multivalued image obtained by the pixel converting unit and the plurality of shift-inverted images obtained by the shift inversion processing unit per pixel corresponding to the multivalued image.
A fourth image half-tone processor according to the present invention comprises an enlarged image forming unit for forming a primary binary image having a size that is (xxc3x97y) times as large as a desired output size, a pixel converting unit for weighting each of pixels of the primary binary image, and converting the primary binary image into a multivalued image consisting of weighted pixel values, a shift processing unit for forming respectively a plurality of shifted images shifted in a plurality of peripheral directions corresponding to a pixel array thereof, a gradation processing unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the plurality of shifted images obtained by the shift processing unit, a reduction processing unit for reducing the half-tone image formed by the gradation processing unit down to a size by a factor of (1/x)xc3x97(1/y), and an image outputting device for outputting the half-tone image formed by the gradation processing unit.
The shift processing unit may be a unit for forming respectively four shifted images into which the primary binary image is shifted in upper-, lower-, left- and right-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shifted images obtained by the shift processing unit.
The shift processing unit may be a unit for forming respectively four shifted images into which the primary binary image is shifted in left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the four shifted images obtained by the shift processing unit.
The shift processing unit may be a unit for forming respectively eight shifted images into which the primary binary image is shifted in upper-, lower-, left-, right-, left-upper-, left-lower-, right-upper- and right-lower-directions, and the gradation processing unit may be a unit for forming a half-tone image on the basis of the multivalued image obtained by the pixel converting unit and the eight shifted images obtained by the shift processing unit.
The gradation processing unit may be a unit for additionally synthesizing the multivalued image obtained by the pixel converting unit and the plurality of shifted images obtained by the shift processing unit per pixel corresponding to the multivalued image.
A fifth image half-tone processor according to the present invention comprises a pixel converting unit for weighting each of pixels of a primary binary image, and converting the primary binary image into a multivalued image consisting of weighted pixel values, a gradation processing unit for forming a half-tone image by gradating the pixel values of the multivalued image on the basis of pixel data corresponding to adjacent pixels peripheral to the respective pixels of the multivalued image, and an image outputting device for outputting the half-tone image formed by the gradation processing unit.
The gradation processing unit may be a unit for executing the gradating process based on the data of the pixels disposed upward, downward, leftward and rightward adjacent to the respective pixels of the multivalued image.
The gradation processing unit may be a unit for executing the gradating process based on the data of the pixels disposed left upward, left downward, right upward and right downward adjacent to the respective pixels of the multivalued image.
The gradation processing unit may be a unit for executing the gradating process based on the data of the pixels disposed upward, downward, leftward, rightward, left upward, left downward, right upward and right downward adjacent to the respective pixels of the multivalued image.
The gradation processing unit may be a unit for executing the gradating process based on the data of such pixels that the pixel values of the respective adjacent pixels are background pixel values.
A sixth image half-tone processor according to the present invention comprises an enlarged image forming unit for forming a primary binary image having a size that is (xxc3x97y) times as large as a desired output size, a pixel converting unit for weighting each of pixels of the primary binary image, and converting the primary binary image into a multivalued image consisting of weighted pixel values, a gradation processing unit for forming a half-tone image by gradating pixel values of the multivalued image on the basis of pixel data corresponding to adjacent pixels peripheral to the respective pixels of the multivalued image, a reduction processing unit for reducing the half-tone image formed by the gradation processing unit down to a size by a factor of (1/x)xc3x97(1/y), and an image outputting device for outputting the half-tone image formed by the reduction processing unit.
The gradation processing unit may be a unit for executing the gradating process based on the data of the pixels disposed upward, downward, leftward and rightward adjacent to the respective pixels of the multivalued image.
The gradation processing unit may be a unit for executing the gradating process based on the data of the pixels disposed left upward, left downward, right upward and right downward adjacent to respective pixels of the multivalued image.
The gradation processing unit may be a unit for executing the gradating process based on the data of the pixels disposed upward, downward, leftward, rightward, left upward, left downward, right upward and right downward adjacent to the respective pixels of the multivalued image.
The gradation processing unit may be a unit for executing the gradating process based on the data of such pixels that the pixel values of the respective adjacent pixels are background pixel values.
The primary binary image may be a character font image.
In the image half-tone processor according to the present invention, each of pixels of a primary binary image is weighted, and the primary binary image is converted into a multivalued image consisting of weighted pixel values. There are formed respectively a plurality of shift-inverted images or shifted imaged into which the primary binary image is inverted and shifted, or shifted without being inverted in a plurality of peripheral directions corresponding to a pixel array of the primary binary image. A half-tone image is formed based on the multivalued image and the plurality of shifted images, and then outputted. Hence, the primary binary image is converted into the multi-gradated image containing such half-tones as to smooth an apparent outline of the primary binary image, and then outputted to give an easy-to-see display with a high visual recognizability.
Further, in another image half-tone processor according to the present invention, after previously forming the primary binary image having a size that is (xxc3x97y) times as large as the desired output size, each of the pixels of the primary binary image is weighted, and the primary binary image is thus converted into the multivalued image consisting of the weighted pixel values. Then, there are formed respectively the plurality of shift-inverted images or the plurality of shifted images into which the primary binary image is inverted and shifted, or shifted without being inverted in the plurality of peripheral directions corresponding to the pixel array thereof. The half-tone image is formed based on the multivalued image and the plurality of shifted images, and thereafter the half-tone image is outputted after being reduced down to a size by a factor of (1/x)xc3x97(1/y).
In still another image half-tone processor according to the present invention, each of the pixels of the primary binary image is weighted, and the primary binary image is converted into the multivalued image consisting of the weighted pixel values. Then, the pixel values of the multivalued image are processed with gradations on the basis of the pixel data corresponding to the adjacent pixels peripheral to the respective pixels of the multivalued image, thereby forming the half-tone image. This half-tone image is then outputted.
In yet another image half-tone processor according to the present invention, after previously forming the primary binary image having a size that is (xxc3x97y) times as large as a desired output size, the respective pixels of the primary binary image are weighted, and the primary binary image is converted into the multivalued image consisting of the weighted pixel values. Then, the pixel values of the multivalued image are processed with gradations on the basis of the pixel data corresponding to the adjacent pixels peripheral to the respective pixels of the multivalued image, thereby forming the half-tone image. Thereafter, this half-tone image is reduced down to a size by a factor of (1/x)xc3x97(1/y), and then outputted.
According to the image half-tone processor of the present invention, in the system for outputting the binary image by use of the outputting device capable of giving the expression with multi-gradations containing the half-tones, the primary binary image is converted into the multi-gradated image containing the half-tones enough to smooth the apparent outline of the primary binary image. Thus, it is possible to output the image based on the multi-gradated expression and to provide the easy-to-see display with the high visual recognizability.